2001 Dodge Dakota Starting problems.

Hello,
I have a 2001 Dodge Dakota Quad Cab SLT, 4.7 L, V8.
It has problems starting sometimes and i think it may be electrical..
The engine turns over fine but she wont fire up..
When it does start it runs great.. no hiccups and plenty of power..
I took it to autozone and had them plug it in and check it and i'm not getting any faults so i have nothing to go by..
When it doesn't start, where the mileage is usually displayed it says NO BUS
and the Gas light comes on.. ( Yes it has gas lol, the tanks full )
Last time i left the key in the on position.. i was sitting in the truck trying to figure it out and about 10 mins in i heard something clicking under the hood so i hit the key and she fired right up... which is why i think it's electrical. and whatever it is is not sending fuel...
I replaced the fuel pump relay but still have the problem...
could it be the fuel pump or injector? Maybe a sensor?
I don't wanna just throw parts at it.. i can't afford to do that...
Thanks,
George